Most people understand what reflexes are – involuntary reactions such as jerking your hand away if something sharp or hot touches you, sneezing in response to allergens, or blinking if an object approaches your eye. Babies possess a unique set of reflexes – known as primitive reflexes – that gradually are replaced by higher level reflexes. If these primitive reflexes persist, they are called retained primitive reflexes.
Primitive reflexes are automatic, non-voluntary movements directed from the brainstem that develop in utero and are integrated as the nervous system develops. Typically, reflexes are integrated within the first two years of life, but the lack of integration may lead to social, academic, or motor learning delays. These delays impact the vestibular system (head in space and balance), proprioception system (input to joints and muscles for body awareness), and tactile system (touch).
Challenges and Behaviors Associated with Retained Primitive Reflexes
Below you’ll find information on the most common primitive reflexes with description and behaviors and challenges associated with retention. Children who are most at risk for retained primitive reflexes are children who were born premature, born via cesarean section, or have a diagnosis of Autism Spectrum Disorder (ASD), attention deficit hyperactivity disorder (ADHD), or sensory processing disorder (SPD).
Any sudden, unexpected occurrence can trigger the moro reflex, which is the body’s “fight or flight” function, releasing cortisol and adrenaline. It begins to develop at nine weeks in utero and is integrated by 2-4 months of age.
- Warning Signs when it has not properly integrated can include: poor impulse control, hypersensitivity, poor attachment to self and others, motion sickness, poor coordination, sensitivity to light, dislike of change or surprises, or physically timid.
Works the balance muscles for sideways rolling of foot, builds foot arches, and places legs for crawling. It begins to develop 12-13 weeks in utero and is integrated by 3 years of age.
- Warning Signs when it has not properly integrated can include: flat feet or very high arches, poor balance
Spinal Galant Reflex
This reflex is triggered by moving your finger down the right or left side of your child’s spine. If your child rotates their hips to the side of the stimulus, then the reflex is not integrated. Spinal Galant reflex is responsible for pelvic up and down movement. It begins to develop 20 weeks in utero and is integrated by 3-9 months of age.
- Warning Signs when it has not properly integrated can include: fidgeting, bedwetting, poor concentration, poor short-term memory, postural issues (scoliosis or lower back pain)
Asymmetrical Tonic Neck Reflex (ATNR)
Movement of baby’s head to one side will result in extension of the arm and leg to the side that the head is turned and bending of the limbs on the other side of the body. It begins to develop 18 weeks in uterus and integrated at about 6 months of age.
- Warning Signs when it has not properly integrated can include: loss of balance with head movement to either side, difficulty crossing midline, poor eye tracking (so reading is hard), poor hand-eye coordination, poor handwriting, poor expression of ideas on paper, difficulty riding a bike and turns the wrong way, and possible dyslexia (both auditory and visual).
Tonic Labyrinthine Reflex (TLR)
TLR is the basis for head management and postural stability with muscle groups. The reflex can be triggered by either moving head forward or backwards, resulting in loss of balance. Balance, muscle tone, and proprioception are all training during this process. This reflex helps the baby “straighten out” from the flexed position in the womb. The first part of the reflex (flexion) begins to develop in utero, and the second part of the reflex (extension) is present at birth. Flexion is integrated at about 4 months of age and extension is integrated at 3 years of age or younger.
- Warning Signs when it has not properly integrated can include: Poor posture (hunched over walking) or walking on tippy toes, weak muscle tone, over-flexible joints, jerky movements, poor sense of balance, motion sickness, fear of heights, fear of walking downstairs or going down escalator, difficulty walking upstairs, visual-perceptual difficulties, tendency to be cross-eyed, spatial challenges, poor sequencing, dislike of sporting activities, poor sense of time, poor organizational skills, clumsiness, and w-sitting with arms turned towards body.
Symmetrical Tonic Neck Reflex (STNR)
This reflex is present when the child is on all four limbs (crawling position) and moving their head towards their chest causes the arms to bend and the legs to extend or moving their head up towards the ceiling (extension) causes the legs to flex and the arms to straighten. The purpose of this reflex is to help the child defy gravity by getting off the floor onto hands and knees from lying on their stomach. It begins to develop 6-9 months of age and integrates 9-11 months of age.
- Warning Signs when it has not properly integrated can include: poor posture, tendency to “slump” when sitting (especially at desk/table), ape-like walk, poor hand-eye coordination (especially copying from board in school), hooking feet around the legs of the chair, w-sitting with arms straight, prefers standing to writing, difficulty riding a bike, and difficulty crawling.
If your child demonstrates any of these behaviors, let your child’s occupational therapist or pediatrician know!
Karlie Moore, MS, OTR/L
Image Courtesy Pixabay/Title Added